What is Myocrisin used for?

How does Myocrisin work?

Myocrisin injection contains the active ingredient sodium aurothiomalate, which is an injectable form of the precious metal gold.

It is not fully understood exactly how this medicine works in rheumatoid arthritis, but it appears to work by dampening down some elements of the body's immune responses, stopping the immune system from attacking the tissues of your joints. This reduces the damaging effects of the disease on your joints and reduces the inflammation and pain of the disease.

Sodium aurothiomalate belongs to a mixed group of medicines called "disease-modifying anti-rheumatic drugs" (DMARDs). Unlike simple painkillers, these medicines actually slow progression of the underlying disease. They can, however, produce more serious side effects.

The effect of the medicine builds up gradually over a few months so you should not expect your symptoms to improve immediately.

How is Myocrisin given?

Myocrisin is given by injection into a muscle. The area will be gently massaged afterwards. You will need to stay in the clinic for 30 minutes after the injection so that you can be monitored for any unwanted effects.

The injection will usually be repeated weekly at first. As your arthritis starts to improve with the treatment the injections can then be given less and less frequently over time. Treatment may be continued for six months to five years if your arthritis responds.

Not everyone responds to gold injections. If your symptoms don't improve with these injections your doctor will need to stop using this medicine and try a different treatment instead.

Important information about Myocrisin

Before starting treatment with this medicine you will need to have blood tests to check your kidney function, liver function and levels of blood cells in your blood. Your urine will also need to be tested for the presence of protein. These tests will need to be repeated throughout your treatment, before each injection, to check that the medicine is not causing any problems. It is important that you do not miss any blood tests that your doctor asks you to have. Once a year your doctor may also want you to have a chest x-ray to make sure your lungs are working properly.

You should consult your doctor immediately if you experience any of the following symptoms, as they could indicate a problem with your blood cells: unexplained bruising or bleeding, purple spots, sore throat or tongue, mouth ulcers, nosebleeds, bleeding gums, high temperature (fever), feeling tired or general illness. Your doctor may want to take a blood test to check your blood cells.

You should also consult a doctor immediately if you develop any of the following symptoms during your treatment, as they could be warnings of potentially serious side effects: eye irritation, hair loss, rash or itching, metallic taste, heavy periods, diarrhoea, cough or breathing difficulties.

While having these injections you should protect your skin from sunlight, even on a bright but cloudy day. This is because sodium aurothiomalate can cause your skin to become discoloured if it is exposed to direct sunlight. Use sunscreen with a high protection factor or cover your skin with clothing. Do not use sunbeds.

Myocrisin should not be used in

People with a history of disturbances in the normal numbers of blood cells in their blood.

People with severe kidney or liver disease.

People with rare inherited metabolic disorders called porphyrias.

People with a long-term condition called systemic lupus erythematosus.

People with skin disease resulting in flaking of the skin (exfoliative dermatitis).

People with scarring and stiffening of the lungs (pulmonary fibrosis).

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction after having an injection you should inform your doctor or nurse immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

The safety of this medicine for use during pregnancy has not been established. The manufacturer states that it is not recommended for use during pregnancy and women who could get pregnant should use an effective method of contraception to prevent pregnancy during treatment. If you think you could be pregnant or want to plan a pregnancy while you are having these injections you should consult your doctor for advice.

This medicine passes into breast milk. As it could theoretically have unwanted effects on a nursing infant, the manufacturer states that mothers who need treatment with this medicine should not breastfeed. Discuss this with your doctor.

Possible side effects of Myocrisin

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Skin rashes or itching. These are usually minor, but as they could indicate the start of a more serious problem you should always let your doctor know if you experience them.

Decreases in the numbers of red blood cells, white blood cells or platelets in the blood. See the important information section above.

Scarring and stiffening of the lungs (pulmonary fibrosis). See the important information section above.

Inflammation of the bowel (colitis).

Liver problems and jaundice.

Kidney problem called nephrotic syndrome.

Allergic reactions.

Hair loss (alopecia).

Skin pigmentation on areas that are exposed to sun. With long-term treatment this may be permanent. See the important information section above.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

If you think you have experienced a side effect from a medicine or vaccine you should check the patient information leaflet. This lists the known side effects and what to do if you get them. You can also get advice from your doctor, nurse or pharmacist. If they think it�s necessary they'll report it for you.

How can Myocrisin affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while having treatment with this one, to make sure that the combination is safe.

There may be an increased risk of allergic reactions if these injections are used in people taking ACE inhibitor medicines such as captopril, enalapril and lisinopril.

There may be an increased risk of side effects on the liver if these injections are used in combination with aspirin.

There may be an increased risk of getting side effects on the liver or blood cells if these injections are used in combination with other medicines that can have similar side effects.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK that contain sodium aurothiomalate as the active ingredient.

Further reading

For background information about our medicine factsheets, including the references used to produce them, click here.

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